Fan-Based Cooler for Head-Protection Gear

ABSTRACT

A cooler accessory for use with a hard hat or other head-protecting gear having a protective shell with a rim, the accessory including a housing that is attachable to the protective shell, tubing that extends from the housing, and airflow supply means (e.g., an electric fan assembly) for supplying a flow of air that passes through the tubing and exits therefrom. During use, the tubing extends below the rim of the protective shell for directing the flow of air supplied by the airflow supply means under the rim for injection toward space adjacent the user&#39;s body, thereby cooling the user&#39;s body. Preferably, the tubing is configured such that airflow is injected into an air gap between the user&#39;s head and the protective shell and over the user&#39;s head, thereby actively cooling the user&#39;s head. The housing can be removably secured to the protective shell of the head protection device by one of many different ways including adhesive means, a strap, clips, a slotted interface or other suitable fixation mechanisms.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates broadly to hard hats for protecting the heads of users in dangerous environments (such as construction sites, mines, forestry and other tree cutting and pruning environments and industrial environments, e.g., chemical plants, assembly plants, steel mills, lumber mills), military helmets, motorcycle helmets, helmets for alpine skiing and/or snowboarding, and other head-protection gear that employ a rigid head-protecting shell. More particularly, the invention relates to mechanisms that are secured to (or part of) the protective shell and operate to cool the user.

2. State of the Art

Environments involving high temperatures, radiant heat sources, high humidity, direct physical contact with hot objects, or strenuous physical activities have a high potential for inducing heat stress in individuals that work in such environments. Such environments include iron and steel foundries, brick-firing and ceramic plants, glass products facilities, rubber products facilities, electrical utilities (particularly boiler rooms), bakeries, confectioneries, commercial kitchens, laundries, food canneries, chemical plants, mining sites, smelters and steam tunnels.

Outdoor operations conducted in hot weather, such as construction, forestry and lumber mills, refining, asbestos removal, and hazardous waste site activities, especially those that require workers to wear semi-permeable or impermeable clothing are also likely to cause heat stress among exposed workers.

In many of these environments, workers wear hard hats that protect the users' heads from failing debris and other potential hazards. However, in hot weather, hard hats provide a “greenhouse” effect where the humidity caused by body perspiration about the head and neck builds up under the hard hat, thereby thwarting the body's own evaporative cooling system. Some leading hard hat manufactures have introduced small air vents similar to the concept disclosed in U.S. Pat. No. 6,170,090 to Minor. However, these small vents provide minimal to no cooling effect. There have been many hard hat designs that actively cool the user by blowing air over the head. Such a design takes advantage of the body's own evaporative cooling system and enhances it with the cooling properties of wind chill. See U.S. Pat. No. Re. 36,242 to Apisdorf, U.S. Pat. No. 3,813,696 to Yeager, U.S. Pat. No. 3,881,198 to Waters, U.S. Pat. No. 3,881,478 to Rosendahl et al., U.S. Pat. No. 4,680,815 to Hirsch et al., U.S. Pat. No. 4,893,356 to Waters, U.S. Pat. No. 5,561,862 to Flores, Sr., U.S. Pat. No. 6,122,773 to Katz, and U.S. Pat. No. 6,760,925 to Maxwell. However, these designs are disadvantageous in that they require modification (e.g., thru-holes) to the protective shell of the hard hat and thus risk compromising the structural integrity of the protective shell. Some standards bodies such as the American National Standards Institute (ANSI) also forbid modification of the hard hat by drilling holes. Moreover, the designs suffer from other limitations including high costs, the inability to remove the active cooling mechanism from the hard hat, the inability to secure the active cooling mechanism to hard hats of varying size, the use of materials that are unsuitable for rugged high-impact environments, and the lack of effective user control over the active cooling function.

Thus, there remains a need in the art to provide an active cooling device for use with a hard hat and other head protection devices with a rigid protective shell that does not require modification to the protective shell (and thus does not risk compromising the structural integrity of the hard hat). Moreover, there remains a need in the art for such an active cooling device that is inexpensive, preferably removable from the protective shell, capable of being added to protective shells of varying size, uses materials that are suitable for rugged high-impact environments, and affords effective user control over the active cooling function.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an active cooling device for use with a hard hat or other head protection device that employs a rigid protective shell that does not require modification to the protective shell (and thus does not risk compromising the structural integrity of the protective shell).

It is another object of the invention to provide such an active cooling device that is inexpensive.

It is a further object of the invention to provide such an active cooling device that is removable from the protective shell.

It is also an object of the invention to provide such an active cooling device that is capable of being added to protective shells of varying size.

It is an additional object of the invention to provide such an active cooling device that is realized from materials that are suitable for rugged high-impact environments.

It is still another object of the invention to provide such an active cooling device that affords effective user control over the cooling function of the device.

In accord with these objects, which will be discussed in detail below, an active cooler accessory device is provided for use with a hard hat or other head-protecting gear having a protective shell with a rim. The accessory device includes a housing that is secured to the protective shell, tubing that extends from the housing, and airflow supply means (e.g., an electric fan assembly) for supplying a flow of air that passes through the tubing and exits therefrom. During use, the tubing extends below the rim of the protective shell for directing the flow of air supplied by the airflow supply means under the rim for injection toward space adjacent the user's body, thereby cooling the user's body. Preferably, the tubing is configured such that airflow is injected into an air gap between the user's head and the protective shell and over the user's head, thereby actively cooling the user's head.

It will be appreciated that the cooling airflow provided by the accessory device can be directed such that it flows over the user's head, which works in conjunction with the body's own evaporative cooling system to significantly reduce the heat and humidity experienced by the user and thus results in a significant increase in the comfort of the user. Such cooling also reduces the exposure to work related heat exhaustion, potential serious heatstroke and reduced productivity.

According to one embodiment of the invention, at least a portion of the tubing is flexible and pliable in order to allow for user control over position and orientation of the tubing. According to another embodiment of the invention, the tubing is relatively stiff and its position and orientation is dictated at the time of manufacture of the tubing.

According to the invention, the housing can be removably secured to the protective shell of a head protection device by one of many ways.

In one embodiment of the invention, the housing is secured to the protective shell by a strap that is securely mounted on (or otherwise affixed to) the housing. The strap has an encircling configuration whereby it wraps around the top surface of the protective shell adjacent its rim. In this encircling configuration, the strap is made snug to the protective shell, thereby securing the housing to the protective shell in a position adjacent its rim. Preferably, the battery compartment is integral to or affixed to the strap and arranged (or capable of movement to such an arrangement) such that in the encircling configuration of the strap, the battery compartment is disposed on the front portion of the protective shell opposite the housing. Such positioning better balances the weight of the accessory device about the perimeter of the protective shell. The accessory device can be detached from the protective shell by removing the strap from its encircling configuration about the top surface of the protective shell.

In another embodiment of the invention, the housing is secured to the protective shell by clips that are securely mounted on (or otherwise affixed to) the housing. The clips interface to and engage the rim of the protective shell. The accessory device can be detached from the protective shell by releasing the engagement of the clips to the protective shell (and/or by releasing the engagement of the clips to the housing).

In yet another embodiment of the invention, the housing is secured to the protective shell by support members that interface to and engage accessory slots formed in the protective shell of the hard hat. Such accessory slots extend upward from the rim of the protective shell typically at opposing positions along the sides of the protective shell. Such accessory slots are typically used for mounting face shield accessories and/or lights on the protective shell.

In yet another embodiment of the invention, the housing is secured to the protective shell by one or more support members that interface to and engage corresponding slot(s) or other mechanical fixation means that are formed in (or affixed to) the protective shell.

The accessory device of the present invention preferably includes a battery compartment, at least one user-manipulated switch and associated control circuitry that operate to selectively couple at least one battery held within the battery compartment to the airflow supply means in response to user manipulation of the at least one switch. According to a preferred embodiment of the invention, a first user-manipulated switch cooperates with control circuitry to operate the airflow supply means in a one of a plurality of different modes, which can include i) a first mode wherein airflow supply means is powered off; ii) a second mode wherein the airflow supply means is automatically cycled on/off for predetermined on/off time periods; and iii) a third mode wherein the airflow supply means is continuously powered on. A second user-manipulated switch cooperates with the control circuitry to operate the airflow supply means in a mode wherein the airflow supply means is automatically powered on for a predetermined time period, with such operations overriding the control operations of the first and second modes.

The accessory device of the present invention preferably includes one or more connectors that connect to an external power source, which can be an external AC/DC power converter (outlet charger), an external DC/DC power converter (automobile cigarette lighter charger), and/or an external solar-cell power converter. The external power source can be used to charge the battery(ies) that are held in the battery compartment of the accessory device, and possibly for powering the airflow supply means of the device.

Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a cooling accessory secured to a hard hat in accordance with the present invention.

FIG. 2A is a perspective view of the cooling accessory of FIG. 1.

FIG. 2B is an exploded view of the cooling accessory of FIG. 1.

FIG. 3 is a side view of the cooling accessory of FIG. 1.

FIG. 4 is an internal view of the electric fan assembly of the accessory of FIG. 1 and the airflow generated thereby for cooling purposes.

FIG. 5 is a blown-up view of a recessed compartment in the housing of the accessory of FIG. 1, which supports a user control switch and two connector ports for connection to external power sources.

FIG. 6 is a schematic diagram of exemplary control circuitry that is supported by the housing of FIG. 1 and provides for smart activation of the electric fan assembly in accordance with user input.

FIG. 7 is a perspective view of the accessory of FIG. 1, with an external solar-cell power source mounted onto its housing.

FIGS. 8A-8C are different views of the accessory of FIG. 1, showing exemplary dimensions for different parts of the accessory.

FIG. 8D is a view of the accessory of FIG. 7, showing exemplary dimensions for the external solar-cell power generator.

FIGS. 9A and 9B are different perspective views of an alternate embodiment of the present invention wherein parts of the active cooling device are integrally formed with the protective shell and rim of a hard hat.

FIG. 10 is a side view of another embodiment of a cooling accessory that is secured to a hard hat in accordance with the present invention.

FIG. 11A is a side view of another embodiment of a cooling accessory secured to a hard hat in accordance with the present invention.

FIGS. 11B-11E are different views of portions of the cooling accessory of FIG. 11A.

FIGS. 12A-12E are different views of the cooling accessory of FIG. 11A, showing exemplary dimensions for different parts of the cooling accessory.

FIGS. 13A-13C illustrate another embodiment of a cooling accessory in accordance with the present invention. FIG. 13A illustrates the cooling accessory employed in its intended use in conjunction with a hard hat and a protective hood in order to supply a source of air to the user when protected by the hood. FIG. 13B illustrates the extension boot of the cooling accessory of FIG. 13A. FIG. 13C is a partial cutaway view of the cooling accessory of FIG. 13A.

FIGS. 14A-14C are views showing exemplary dimensions for parts of the cooling accessory of FIGS. 13A-13C.

FIG. 15A is a perspective view of another embodiment of a cooling accessory that is removably securable to a hard hat in accordance with the present invention.

FIGS. 15B-15F are different views of portions of the cooling accessory of FIG. 15A.

FIGS. 16A-16I are different views of the cooling accessory of FIG. 15A, showing exemplary dimensions for different parts of the cooling accessory.

FIGS. 17A-17C are different views of yet another embodiment of a cooling accessory that is removably securable to a hard hat in accordance with the present invention.

FIG. 18 is a schematic diagram of exemplary control circuitry that can be supported by any one of the housings of FIGS. 11A, 13A, 15A and 17A to provide for smart activation of the electric fan assembly in accordance with user input.

DETAILED DESCRIPTION

The term “hard hat” as used herein is meant to include not only the specific designs shown, but also include other types of head-protecting safety hats for dangerous environments (such as construction sites, mines, forestry and other tree cutting and pruning environments and industrial environments, e.g., chemical plants, assembly plants, steel mills, lumber mills), military helmets, motorcycle helmets, helmets for alpine skiing and/or snowboarding, and other head-protection gear that employ a rigid head-protecting shell.

Turning now to FIG. 1, an exemplary hard hat 10 includes a molded, hard plastic protective shell 12 with a rim 14 surrounding a domed-shaped head cover portion 16 that defines a head-receiving cavity 18 therein. A head support harness (not shown) is affixed to the interior surface of the dome-shaped head cover portion 16 and is disposed within the head-receiving cavity 18. The head-support harness interfaces to the user's head and supports the shell 12 above the user's head such that an air gap exists therebetween. A cooling accessory 21 is affixed to the exterior surface of the shell 12, preferably to the rear portion of the shell 12 as shown.

As best shown in FIGS. 2A, 2B and 3, the cooling accessory 21 includes a rigid plastic housing 23 preferably realized from three distinct housing parts 23A, 23B, 23C (FIG. 2B). The housing part 25C has a curved base 25 that generally follows the contour of the domed-shaped portion 16 of the protective shell 12. In the preferred embodiment, the housing parts 23A, 23B, 23C are realized from a lightweight material suitable for high-impact applications such as a high density polyethylene, an acrylonitrile-butadiene-styrene (ABS) copolymers or polypropylene or other suitable plastic suitable for high impact applications, carbon fiber, Kevlar, or other high impact material.

As best shown in the exploded view of FIG. 2B, a flexible insert 27 of elastomeric material (such as rubber or neoprene) is fixed to the base 25 preferably with an adhesive layer. One or more hook-and-loop fastener pads (not shown) may be adhesively affixed to the insert 27 preferably by the user and then secured to the protective shell 12 to locate the accessory 21 on the exterior surface of the protective shell 12 and then remove it if desired. Alternatively, the base 25 and/or the insert 27 may be adhesively fixed to the protective shell 12. The insert 27 provides a cushion for mounting the housing 23 onto the exterior surface of the protective shell 12 in a manner that accommodates protective shells with varying shapes and sizes (e.g., varying radii of curvature). This allows the accessory 21 to be mounted on hard hats with varying shapes and sizes. Rubber trim 28 may surround the edge of the curved base 25 in order to hide a gap that may exist between the curved base 25 and the protective shell 12. The rubber trim 28 also keeps dust and debris away from the curved base 25 and the interface between the base 25 and the protective shell 12.

As best shown in FIG. 2B and FIG. 4, the housing part 23A defines an opening 29 that leads to an air duct 31 within the housing part 23B. A grille 33 covers the opening 29. An electric fan assembly 35, comprising a fan blade 37 driven by an electric motor 39, is mounted axially within the air duct 31. A hose 41 is coupled to the bottom of the housing part 23C in fluid communication with air duct 31. The electric fan assembly 35, when powered on, operates to draw air into the opening 29 and through the air duct 31 and hose 41 where it exits from the end port 43 of the hose. The grille 33 may be removeable by the user such that the user can access the fan blade 37 (and possibly the electric motor 39) for cleaning and maintenance as required. In the preferred embodiment, the air duct 31 and the electric fan assembly 35 are adapted to produce airflow through and out the hose 41 in a range between 14 to 16 cfm. The hose 41 is realized from a flexible and pliable construction that enables the user to adjust the position and orientation of the end port 43 in order to control the direction of the airflow that exits therefrom as desired. Moreover, the construction of the hose 41 preferably allows for extension of the hose 31 along its length to further provide greater flexibility in user positioning of the end port 43. In the preferred embodiment, the hose 41 is constructed of corrugated rubber, silicone or poly-elastomeric material and has a length that can vary between 50 mm and 170 mm. The user extends the hose 41 by applying an axially pulling force (e.g., away from the housing) to a desired section of the hose 41. The user shortens the hose 41 by applying an axial pushing force (e.g., toward the housing) to a desired section of hose. The lengthwise extendibility of the hose 41 also allows the device to be used on hard hats with different rim sizes (e.g., no-brim hard hats, short-brim hard hats, long-brim hats, and possibly Western-style hard hats).

During use, the air duct 31 is positioned substantially orthogonal relative to the plane defined by the rim 14 as best shown in FIG. 1. In this manner, the air duct 31 and electric fan assembly 35 are typically disposed in a substantially vertical position during use. A portion of the flexible hose 41 is positioned under the rim 14 such that the airflow produced by the electric fan assembly 35 flows under the rim 14 of the hard hat 10. The end port 43 of the hose is positioned such that airflow exiting therefrom is directed to flow towards or around a part of the user's body for cooling purposes. Preferably, the end port 43 of the hose is positioned such the exiting airflow is injected upward from the rear of the hard hat 10 into the air gap between the user's head and the protective shell 12 and up over the head where it is then exhausted below the front of the hard hat 10. In this configuration, the airflow passes over the back, top and front of the user's head, which provides a maximal cooling effect. Note that the tube 41 generally has a u-shape along its length in order to guide the airflow under the rim 14 of the hard hat 10 and eject it upward into the air gap between the user's head and the protective shell 12. Alternatively, the end port of the host can be positioned such that the airflow is directed towards or around other parts of the head (e.g., the base of the head), the neck, or other part(s) of the body.

The housing 23 includes a battery compartment 38 (not shown) that holds one or more batteries that supply electrical power to the electric motor 39 of the fan assembly 35. The housing part 23C also supports a printed circuit board (FIG. 6) mounted therein that includes a microcontroller 51 and associated circuitry. The microcontroller 51 interfaces to switching circuitry 53 that selectively closes and opens one or more current paths that allow the battery(ies) 38 to power on and off the electric motor 39 of the fan assembly 35. The microcontroller 51 also interfaces to a set of one or more user-operated switches (e.g., two switches 45A and 45B—see FIG. 6) that are supported by the housing 23. The one or more user-operated switches allow the user to control the operation of the electric motor 39 to thereby activate the cooling fan function provided by the device.

In the preferred embodiment, two switches 45A and 45B are used. As best shown in FIG. 5, the first switch 45A is a three-position switch that is disposed in a recessed compartment 47 of the housing and accessible by a removable cover 49 (FIG. 1). In this configuration, the first switch 45A is protected from direct impact forces (which can be experienced if the hard hat 10 is dropped or otherwise impacted) as well as from direct environmental factors (e.g., rain, snow, dust, etc). The second switch 45B, which is preferably realized as an ergonomically designed larger-size button switch preferably with a diameter greater than 15 mm (and most preferably in a range between 20 mm and 30 mm in a range) as best shown in FIGS. 1-3 and 8B, is disposed on the exterior of the housing 23 for quick user access. In this configuration, the second switch 45B is specifically designed to withstand a degree of direct impact forces (which can be experienced if the hard hat 10 is dropped or otherwise impacted) as well as a degree of direct environmental factors (e.g., rain, snow, dust, etc). The second switch 45B also preferably provides tactile feedback that enables the user to operate the switch 45B with work gloves that are commonly used in such dangerous environments. In the preferred embodiment, the second switch 4

As shown in the schematic diagram of FIG. 6, the first switch 45A and second switch 45B interface to the microcontroller 51, for example a PIC 16F630 microcontroller, which is commercially available from Microchip Technology, Inc. of Chandler, Ariz. The microcontroller 51 also interfaces to a switching circuit 53 (e.g., a field-effect transistor Q1) that selectively opens and closes a current path (e.g., the ground path between the H4 terminal of the electric motor 39 and ground potential) that allows the battery(ies) 38 to power on and off the electric motor 39.

The first switch 45A cooperates with the microcontroller 51 to carry out three different operations modes as follows:

-   -   i) “∘” position—Off Mode: the switching circuitry 53 is         controlled so that electric motor 39 is powered off—the         transistor Q1 is switched OFF so that the ground current path is         inactive);     -   ii) “A” position—Intermittent Mode: the switching circuitry 53         is controlled so that the electric motor is automatically cycled         on/off for predetermined on/off time periods (e.g., on for one         minute and then off for four minutes)—the transistor Q1 is         automatically cycled on/off for predetermined on/off time         periods so that the ground current path is cycled on/off;     -   iii) “” position—Continuous Mode: the switching circuitry 53 is         controlled so that electric motor 39 is continuously powered         ON—the transistor Q1 is switched ON so that the ground current         path is continuously active.         Preferably, the power capacity of the battery(ies) held in the         battery compartment, the power consumption characteristics of         the electric motor 39 and the associated control circuitry, and         the predetermined ON/OFF time periods of the Intermittent mode         are adapted such that the electric motor 39 can operate in the         Intermittent mode for an 8 to 10 hour time period. In this         configuration, the Intermittent mode is advantageous because the         device can be used to cool the user for an entire work day (or a         substantial part of a long work day) on a single battery charge.         The Intermittent mode has other advantages. More particularly,         during the OFF time periods, heat and moisture will typically         build up under the protective shell 12 and cause the user to         perspire. In the ON mode, the air blown over the head will         enhance the evaporative-based cooling provided by such         perspiration for an improved cooling effect.

The second switch 45B cooperates with the microcontroller 51 to carry out a “Fast-Blast” mode wherein the switching circuitry 53 is controlled to power ON the electric motor 39 for a predetermined time period (e.g., two minutes)—the transistor Q1 is automatically cycled on for the predetermined time period so that the ground current path is activated for the predetermined time period. In such operations, the “Fast-Blast” mode overrides the “OFF” and “Intermittent” modes such that the “Fast-Blast” mode takes precedence over the control of the switching circuitry 53 (e.g., transistor Q1) and governs the operation of the electric motor 39.

Referring back to FIG. 5, the housing part 23B preferably includes a first connector port 51A for connecting to an external AC/DC power converter (outlet charger) or to an external DC/DC power converter (automobile cigarette lighter charger) (not shown), and a second connector port 51B for connecting to an external solar-cell power generator 53 (FIG. 7). Alternatively, these two external power sources may be connected to the same connector. The connector port(s) are preferably located in the same recess as the first switch 45A as shown for protection against direct impact and environmental factors. The printed circuit board supported within the housing also includes charging circuitry, operably coupled between the connector port(s) and the battery(ies) held in the battery compartment, that operates to charge the battery(ies) using the electrical power signal(s) supplied thereto by the external power source. The external power sources (e.g., the solar-cell power generator 53) may also be used in conjunction with the battery(ies) to supply power to the electric motor 39 of the electric fan assembly during use. Alternatively, the external power sources (e.g., the solar-cell power generator 53) may be as a substitute for the battery(ies) to thereby supply power to the electric motor 39 of the electric fan assembly during use, without charging the batteries. In preferred embodiment, the external solar-cell power generator 53 is part of a unitary construction 23A′ that is removably secured to the top of housing part 23C about the opening 29 where it is positioned above the curved base 25 as shown in FIG. 7. A wire (not shown) connects the solar-cell power generator 53 to the second connector port 51B for charging/powering the device.

The dimensions of an exemplary embodiment of the cooling accessory of the present invention is shown in FIGS. 8A-8C. The overall height of the housing 23 is on the order of 112 mm. The diameter of the housing part 23C that defines the air duct 31 is on the order of 64 mm in diameter. The width of the curved base 25 is on the order of 82 mm. In another exemplary embodiment shown in FIG. 8D, the housing part 23A′ is extended above the curved base 25 for mounting an external solar-cell power generator 53 thereon as shown in FIG. 7. In this embodiment, the external solar-cell power generator 53 is on the order of 94 inches wide and 54 inches in length.

In an alternate embodiment shown in FIGS. 9A and 9B, the housing 23′ (or parts thereof) of the active cooling device 21′ is integrally formed (preferably by injection molding) with the protective shell 12′ and rim 14 of a hard hat 10′. In this alternate embodiment, means for securing the housing of the cooling device to the hard hat are omitted and the active cooling device 21′ includes the same functional elements and structural elements as the accessory 21 as described above, and operates in the same manner as the accessory 21 as set forth above.

In yet another alternate embodiment shown in FIG. 10, the opening 29″ defined by the housing parts 23A″ and 23C″ of the active cooling device 21″ is angled downward at an angle α+90° relative to the central axis of the air duct 31″ as it extends away from the top of the curved base portion 25. In the illustrative embodiment shown, the angle α is on the order of 20°. It is contemplated that the angle α may have another value between 0° and 30°, or possibly a larger angle value. Moreover, in this alternate embodiment, the lower housing 23B″ and the hose 41″ are realized as a single unitary plastic part that is formed by injection molding of plastic. The active cooling device 21″ includes the same functional elements and structural elements as the accessory 21 as described above, and operates in the same manner as the accessory 21 as set forth above.

Turning now to FIGS. 11A-11E, an active cooling device 121 in accordance with the present invention is depicted secured to the protective shell 112 of a hard hat 110. The cooling device 121 includes a housing 123 realized from a lightweight thin-walled material supported by structural ribbing such that the device is suitable for high-impact applications. The material of the housing 123 can be an acrylonitrile-butadiene-styrene (ABS) copolymer or polypropylene or other suitable plastic suitable for high impact applications, carbon fiber, Kevlar, or other high impact material. As best shown in FIGS. 11A and 11C, the rear-facing portion of the housing 123 defines an air intake port 129 that leads to an electric fan assembly 135 mounted within the housing 123. The electric fan assembly 135, which is a centrifugal design, includes an impeller that is rotated by an electric motor about a central rotational axis 136. The impeller includes sets of blades which form a spiral pattern. The rotation of the blades of the impeller draws in air from the air intake port 129 and blows the incoming air at right angles relative to rotational axis 136 towards an exhaust port 137 disposed in the bottom portion of the housing 123. A grille 133 covers the air intake port 129. The grille 133 may be removable by the user such that the user can access the electric fan assembly 135 for cleaning and maintenance as required.

An annular strap 142 extends from a pair of support bosses 143A, 143B that project outward from opposite sidewalls of the housing 123. The strap 142 is used to removably secure the cooling device 121 to the protective shell 112 of the hard hat 110 as desired. In the preferred embodiment, the strap 142 includes two portions 144A, 144B that extend forward to a battery compartment 153 secured thereto. Preferably, the battery compartment 153 is curved to generally conform to the outer surface of the protective shell 112 of the hard hat 110. The strap portions 144A, 144B can terminate at the battery compartment 153 or possibly continue therethrough (or outside the battery compartment 153) as part of a unitary strap member. The strap portions 144A, 144B are realized from an elastomeric material that is capable of resiliently stretching such that the user can adjust the circumference of the strap 142, thereby allowing the cooling device 121 to be readily secured to different size hard hats. In this manner, the strap 142 can be adapted for an encircling configuration whereby it extends around the top exterior surface of the protective shell 112 adjacent its rim and support the housing 123 in a position whereby the bottom wall of the housing 123 is adjacent the rim of the protective shell 112 as shown in FIG. 11A. The cooling device 123 can be detached from the protective shell 112 by removing the strap 142 from its encircling configuration about the top exterior surface of the protective shell 112.

Alternatively, the strap can be realized from overlapping portions that are secured together by one or more fixation members which allow the user to select the amount of overlap of the strap portions. This configuration also allows the user to adjust the circumference of the strap 142, thereby allowing the cooling device 121 to be readily secured to different size hard hats.

Preferably, the strap 142 is adapted such that the housing 123 is positioned above the rear portion of the protective shell 112 and the battery compartment 153 is positioned above the front portion of the protective shell 112 opposite the housing 123. Such positioning better balances the weight of the cooling device 123 about the perimeter of the protective shell 112.

Pair of struts 146A, 146B extend forward from the sidewalls of the housing 123 above the support bosses 143A, 143B, respectively. In use, the terminal ends of the struts 146A, 146B contact the rear-facing outer surface of the protective shell 112 above the rim 114 for supporting the device 121 thereon. The terminal ends of the struts 146A, 146B are curved in a manner that mimics the contour of the protective shell 112 for conformance thereto. The terminal ends of the struts 146A, 146B are preferably realized from a soft rubber or rubber-like material to allow for conformance to the protective shell. The struts 146A, 146B also provide for clearance of ornamental raised details on certain hard hats.

A hose 147 extends from the exhaust port 137 disposed in the bottom wall of the housing 123. The hose 147 is adapted to direct air flow from the exhaust port 137 under and around the rim 114 of the protective shell 112 and then generally upwards into the air gap between the user's head and the protective shell 112 for cooling purposes. In the preferred embodiment as best shown in FIG. 11D, the hose 147 extends generally downward from the exhaust port to a 180 degree elbow portion 149 that extends generally below and around the rim 114 of the protective shell 112. An end portion 151 extends from the elbow portion 149 in a generally upward direction. In the preferred embodiment, the end portion 151 extends upward to an elevation above the top surface of strap 142 and near the elevation of the top surface of the housing 123 as shown. The bore size of the hose 147 generally decreases along its length as best shown in FIG. 11D. In the preferred embodiment, the hose 147 is constructed of high density polyethylene and is stiff such that the position and orientation of the hose is fixed. Alternatively, the hose 147 can be flexible to allow for desired forgiveness and bendability. The hose 147 can also be pliable and extendable to allow for user adjustability of the hose orientation and/or length.

In the preferred embodiment, the strap 142 includes electrical conductors 155 that supply electrical energy from batteries housed in the battery compartment 153 to the electric motor of the electric fan assembly 135. One or more wire supports (two shown as 156A, 156B) are provided to support the electrical conductors 155 that extend between the housing 123 and the battery compartment 153. In the illustrative embodiment shown, the wire supports 156A, 156B include one or more guide channels through which the electrical conductors 155 extend. Preferably, the guide channel(s) is(are) sized so that the one or more electrical conductors that extend therethrough can freely slide within the channel(s) to allow for adjustability of the strap circumference.

During use, the hose 147 directs air flow from the exhaust port 137 under and around the rim 114 of the protective shell 112 and then generally upwards into the air gap between the user's head and the protective shell 112 for cooling purposes. In this configuration, the airflow passes over the back, top and front of the user's head, which provides a maximal cooling effect. Note that the hose 147 generally has a u-shape along its length in order to guide the airflow under the rim 114 of the protective shell 112 and eject it upward into the air gap between the user's head and the protective shell 112.

The housing 123 also supports a printed circuit board (FIG. 18) mounted therein, which includes a microcontroller and associated circuitry as described above. The microcontroller 181 interfaces to switching circuitry (transistor Q3) that selectively closes and opens a current path that allows electric energy supplied by one or more batteries loaded into the battery compartment 153 to power on and off the electric motor of the electric fan assembly 135. The microcontroller 181 also interfaces to a set of two user-operated switches 175A, 175B that allow the user to control the operation of the electric motor of the electric fan assembly 135 to thereby activate the cooling fan function provided by the device. The first switch 175A is disposed on the top wall of the housing 123. The second switch 175B, which is preferably realized as an ergonomically designed larger-size button switch as described above, is disposed within the central region of the grill 133 as best shown in FIG. 11C. The second switch 175B also preferably provides tactile feedback that enables the user to operate the switch 175B with work gloves that are commonly used in such dangerous environments.

In the preferred embodiment, the first switch 175A cooperates with the microcontroller 181 to carry out two different operations modes as follows:

-   -   i) Off Mode: the switching circuitry (transistor Q3) is         controlled so that the electric motor of the electric fan         assembly 135 is powered off; and     -   ii) Intermittent Mode: the switching circuitry (transistor Q3)         is controlled so that the electric motor of the electric fan         assembly 135 is automatically cycled on/off for predetermined         on/off time periods (e.g., on for one minute and then off for         five minutes).         Preferably, the power capacity of the battery(ies) held in the         battery compartment 153, the power consumption characteristics         of the electric motor and the associated control circuitry, and         the predetermined ON/OFF time periods of the Intermittent mode         are adapted such that the electric motor can operate in the         Intermittent mode for an 8 to 10 hour time period. In this         configuration, the intermittent mode is advantageous because the         cooling device 123 can be used to cool the user for an entire         work day (or a substantial part of a long work day) on a single         battery charge. The Intermittent mode has other advantages. More         particularly, during the OFF time periods, heat and moisture         will typically build up under the protective shell 112 and cause         the user to perspire. During the ON periods, the air blown over         the head will enhance the evaporative-based cooling provided by         such perspiration for an improved cooling effect.

In the preferred embodiment, the second switch 175B cooperates with the microcontroller 181 to carry out a “Fast-Blast” mode wherein the switching circuitry (transistor Q3) is controlled to power ON the electric motor of the electric fan assembly 135 for a predetermined time period (e.g., one minute). In such operations, the “Fast-Blast” mode overrides the “OFF” and “Intermittent” modes such that the “Fast-Blast” mode takes precedence over the control of the switching circuitry and governs the operation of the electric motor.

Referring back to FIG. 11C, the housing part 123 (or other part of the device) preferably includes at least one connector 177 that connects to an external power source. The connector(s) 177 can provide a connection to an external AC/DC power converter (outlet charger), an external DC/DC power converter (automobile cigarette lighter charger), and/or an external solar-cell power converter. The external power source can be used to charge the battery(ies) that are held in the battery compartment 153 of the accessory device, and/or possibly for powering the electric fan assembly 135 of the device.

FIGS. 12A-12E show the dimensions of an exemplary embodiment of a cooling device 121′ in accordance with the present invention. The housing 123′ has a height on the order of 3 inches and a depth on the order of 1.77 inches (FIG. 12A). These dimensions generally define the size of the electric fan assembly 135′ supported therein. The support bosses 143A′, 143B′ have a width on the order of 0.46 inches (FIG. 12D) and extend beyond the respective sidewalls of the housing 123′ on the order of 0.615″ in length (FIG. 12B). The hose 147′ has a bore size on the order of 1.44 inches wide throughout its length with a thickness on the order of 0.95 inches adjacent the exhaust port and a thickness on the order of 0.36 inches at its terminal end (FIGS. 12A and 12B). The strap 142′ has a height on the order of 1.19 inches (FIG. 12A) and has a circumference in its encircling configuration which can range from 26 inches to 28.5 inches.

Turning now to FIGS. 13A-13C, the active cooling device 121 of FIGS. 11A-11E is modified for use in conjunction with a protective hood 1001 that is placed over a hard hat 110. In the illustrative embodiment shown, the protective hood 1001 covers the head, neck and upper torso of the user and is realized from material that protects against arc flashes. The protective hood 1001 includes a lens 1003 disposed about its front side that provides for transmission of visible light therethrough while protecting against arc flashes. The protective hood 1001 includes front and back panels 1005A, 1005B that are disposed opposite one another and cover the upper torso of the user as shown. The active cooler device 121 is removably secured to the protective shell 112 of the hard hat 110 with a strap 142 as described above. An intake boot 181 is secured to the housing 123 of the cooling device 121 by a snap fit or other mechanical fixation mechanism (e.g., screws). The top portion 183 of the intake boot 181 covers the intake port 129 leading to the electric fan assembly 135. An extension tube 185 extends from the bottom of the top portion 183 generally downward. The length of the extension tube 185 is adapted such that it extends below the protective hood (i.e., below the back panel 1005B of the protective hood 1001 as shown). In this manner, the terminal end 186 of the extension tube 185 provides for intake of air by the active cooler device 121 in a manner that is unencumbered by the protective hood 1001. During use, the hose 147 of the active cooling device 123 directs air flow under and around the rim of the protective shell 112 and then generally upwards into the air gap between the user's head and the protective shell 112 for cooling purposes. In this configuration, the airflow passes over the back, top and front of the user's head, which provides a supply of air to the user and a cooling effect. This supply of air would otherwise be limited by the protective hood 1001.

As best shown in FIGS. 13B and 13C, the extension tube portion 187 adjacent the top portion 183 includes a plurality of ribs 188, which can be used to demarcate trim points for user customization of the length of the extension tube 185. In the preferred embodiment, the intake boot 181 is constructed of fire resistant material and is stiff such that the position and orientation of the intake boot is fixed. Alternatively, the intake boot 181 can be flexible to allow for desired forgiveness and bendability. The terminal end of the intake boot 181 can also be pliable and extendable to allow for user adjustability of its orientation and/or length.

As shown in FIG. 13C, the top portion 183 of the intake boot 181 covers the switch 175B disposed in the central region of the intake port 129. In order to provide user control of switch 175B, the top portion 183 includes a boss 189 that extends inward from the rear-facing wall of the top portion 183 and contacts the switch 175B. In this manner, the user can press on the rear-facing wall portion that overlies the boss 189 in order to interface with the switch 175B and turn it ON and OFF.

FIGS. 14A-14C illustrate the dimensions of an exemplary embodiment of an intake boot 181′ suitable for use with the cooling device 121′ of FIGS. 12A-12E. The intake boot 181′ has a total length on the order of 25 inches (FIG. 14A). The top portion 183′ has a width on the order of 3.3 inches (FIG. 14B) and a depth on the order of 1.21 inches (FIG. 14C). The extension tube 185′ has a thickness on the order of 0.67 inches throughout its length (FIG. 14C), a width on the order of 1.77 inches adjacent the top portion 183′ and a width on the order of 1.37 inches between section 187′ and the terminal end 186′ (FIG. 14B).

Turning now to FIGS. 15A-15F, an active cooling device 221 in accordance with the present invention is secured to the protective shell 112 of a hard hat 110 in use. The cooling device 221 includes a housing 223 realized from a lightweight thin-walled material supported by structural ribbing such that the device is suitable for high-impact applications. The material of the housing 223 can be an acrylonitrile-butadiene-styrene (ABS) copolymer or polypropylene or other suitable plastic suitable for high impact applications, carbon fiber, Kevlar, or other high impact material. The rear-facing portion of the housing 223 defines an air intake port 229 that leads to an electric fan assembly 235 mounted within the housing 223. The electric fan assembly 235, which is an axial design, includes an impeller that is rotated by an electric motor about a central rotational axis 236. The impeller includes sets of blades whose rotation draws in air from the intake port 229 and blows the incoming air parallel to rotational axis 236 towards an exhaust port 230 disposed in the front-facing wall of the housing 223. A grille 233 covers the air intake port 229.

Pair of wings 243A, 243B extend outward from the top portion of the housing 223 in a curved fashion that generally conforms to the curvature of the rear-portion of the rim 114 of the protective shell 112 of the hard hat 110. Each wing 243A, 243B preferably supports an internal battery compartment (not shown) as well as internal electrical conductors (not shown) for supplying electrical energy from the battery(ies) housed in the respective battery compartment to the electric motor of the fan assembly 235.

As best shown in FIG. 15C, a set of clips 251 (for example, three shown) removably affix the housing 223 and wings 343A, 243B to the rear portion of the rim 114 of the protective shell 112. The clips 251 engage the top portion of the rim 114 to secure the apparatus in place adjacent the rim 114. In the preferred embodiment, the clips 251 each have a u-shaped cross-section with a forward-facing space defined between a top portion and a bottom portion. The bottom portion of the clip is secured to the housing 223 by screws, rivets or other suitable mechanical fixation mechanisms. The rim 114 of the protective shell 112 is operably disposed within the forward-facing space defined between its top and bottom portion. A screw 253 (such as an Allen screw or butterfly screw) is inserted through threaded thru-holes of the top portion of the clip to engage the exterior top surface of the rim 114, thereby securing the clips 251 to the rim 114 as shown.

As shown in FIGS. 15D and 15E, a hose 247 is affixed to the housing 223 such that it covers the exhaust port 230. Preferably, the hose 247 is removably affixed to the housing 223 by a snap fit connection or other suitable mechanical fixation means. The hose 247 is adapted to direct air flowing through the exhaust port 230 under and around the rim 114 of the protective shell 112 and then generally upwards into the air gap between the user's head and the protective shell 112 for cooling purposes. In the preferred embodiment, the hose 247 includes a dome section 248 that covers the exhaust port 230 and directs the air flowing through the exhaust port 230 from its incoming axial direction upward to a tubular section 249 that extends generally upward. The dome section 248 and tubular section 249 of the hose 247 are preferably realized from a flexible and pliable construction that enables the user to adjust the position and orientation of the tubular section 249 in order to control the direction of the airflow that exits therefrom as desired. Moreover, the construction of the tubular section 249 preferably allows for extension along its length to further provide greater flexibility in user positioning of the tubular section. In the preferred embodiment, the dome section 248 and tubular section 249 are constructed of corrugated rubber, silicone or poly-elastomeric material. The adjustability of the hose 247 also allows the device to be used on hard hats with different rim sizes (e.g., no-brim hard hats, short-brim hard hats, long-brim hats, and possibly Western-style hard hats). In the preferred embodiment, the tubular section 249 extends (or is extendable) upward to an elevation above the top surface of housing 223 and wings 243A, 243B as shown. In alternate embodiments, the hose 247 can be fixed-length and stiff such that the position and orientation of the hose is fixed, or the hose 247 can be fixed-length and flexible to allow for desired forgiveness and bendability.

During use, the hose 247 directs air flow from the exhaust port 230 under and around the rim 114 of the protective shell 112 and then generally upwards into the air gap between the user's head and the protective shell 112 for cooling purposes. In this configuration, the airflow passes over the back, top and front of the user's head, which provides a maximal cooling effect.

In an alternate configuration shown in FIGS. 15F and 15G, a grill 251 is affixed to the housing 223 such that it covers the exhaust port 230. Preferably, the grille 251 is removably affixed to the housing 223 by a snap fit connection or other suitable mechanical connection means. In this configuration, the air flowing generally axially through the exhaust port 230 continues through the grille 251 such that it is directed to the back of the neck of the user.

The housing 223 also supports a printed circuit board (FIG. 18) mounted therein, which includes a microcontroller and associated circuitry as described above. The microcontroller 181 interfaces to switching circuitry (transistor Q3) that selectively closes and opens a current path that allow electric energy supplied by one or more batteries loaded into the battery compartment(s) of the device to power on and off the electric motor of the electric fan assembly 135. The microcontroller 51 also interfaces to a set of two user-operated switches 275A, 275B (which are substitutes for the switches 175A, 175B as shown) that allow the user to control the operation of the electric motor of the electric fan assembly 235 to thereby activate the cooling fan function provided by the device. The first switch 275A is disposed on the housing 223 or one of the wings 243A, 243B. In the preferred embodiment, the first switch 275A is disposed at the terminal end of one of the wings (for example, the terminal end of wing 243B as shown). The second switch 275B, which is preferably realized as an ergonomically designed larger-size button switch as described above, is disposed within the central region of the grill 233 as best shown in FIGS. 15A and 15C. The second switch 275B also preferably provides tactile feedback that enables the user to operate the switch 275B with work gloves that are commonly used in such dangerous environments.

In the preferred embodiment, the first switch 275A cooperates with the microcontroller 181 to carry out two different operations modes as follows:

i) Off Mode: the switching circuitry (transistor Q3) is controlled so that the electric motor of the electric fan assembly 235 is powered off; and

-   -   ii) Intermittent Mode: the switching circuitry (transistor Q3)         is controlled so that the electric motor of the electric fan         assembly 235 is automatically cycled on/off for predetermined         on/off time periods (e.g., on for one minute and then off for         five minutes).         Preferably, the power capacity of the battery(ies) held in the         battery compartment(s) of the device, the power consumption         characteristics of the electric motor and the associated control         circuitry, and the predetermined ON/OFF time periods of the         Intermittent mode are adapted such that the electric motor can         operate in the Intermittent mode for an 8 to 10 hour time         period. In this configuration, the intermittent mode is         advantageous because the cooling device 221 can be used to cool         the user for an entire work day (or a substantial part of a long         work day) on a single battery charge. The Intermittent mode has         other advantages. More particularly, during the OFF time         periods, heat and moisture will typically build up under the         protective shell 112 and cause the user to perspire. During the         ON periods, the air blown over the head will enhance the         evaporative-based cooling provided by such perspiration for an         improved cooling effect.

In the preferred embodiment, the second switch 275B cooperates with the microcontroller 181 to carry out a “Fast-Blast” mode wherein the switching circuitry (transistor Q3) is controlled to power ON the electric motor of the electric fan assembly 235 for a predetermined time period (e.g., one minute). In such operations, the “Fast-Blast” mode overrides the “OFF” and “Intermittent” modes such that the “Fast-Blast” mode takes precedence over the control of the switching circuitry and governs the operation of the electric motor.

Referring back to FIG. 15A, the housing part 223 (or other part of the device) preferably includes at least one connector 277 that connects to an external power source. The connector(s) 277 can provide a connection to an external AC/DC power converter (outlet charger), an external DC/DC power converter (automobile cigarette lighter charger), and/or an external solar-cell power converter. The external power source can be used to charge the battery(ies) that are held in the battery compartment(s) of the accessory device, and/or possibly for powering the electric fan assembly 235 of the device.

FIGS. 16A-16I show the dimensions of an exemplary embodiment of a cooling device 221′ in accordance with the present invention. The housing 223′ has a height on the order of 3 inches and a depth on the order of 0.77 inches (FIGS. 16A and 16D). These dimensions generally define the size of the electric fan assembly 225′ supported therein. The wings 243A′, 243B′ span a distance on the order of 6.14 inches (FIG. 16B) and are on the order of 0.65 inches in depth (FIG. 16D). The total depth of the device 221′ is on the order of 2.35 inches (FIG. 16D). The rear-facing grille 235′ has a diameter on the order of 2.59 inches (FIGS. 16A and 16B). The clips 253′ have a width in the range between 0.84 inches and 0.9 inches (FIG. 16E). The hose 247′ is extendable to a length on the order of 6 inches (FIG. 16F). The dome section 248′ has a diameter on the order of 2.51 inches (FIG. 16G). The tubular section 249′ has a width on the order of 1.34 inches, a thickness on the order of 0.56 inches and a length on the order of 3.81 inches (FIGS. 16F and 16G). FIGS. 16H and 16I show the dimensions of the rear grille 251′.

Turning now to FIGS. 17A-17C, an active cooling device 321 in accordance with the present invention is secured to the protective shell 112 of a hard hat 110 in use (FIG. 17C). The cooling device 321 includes a housing 323 realized from a lightweight thin-walled material supported by structural ribbing such that the device is suitable for high-impact applications. The material of the housing 323 can be an acrylonitrile-butadiene-styrene (ABS) copolymer or polypropylene or other suitable plastic suitable for high impact applications, carbon fiber, Kevlar, or other high impact material. A face of the housing 323 defines an air intake port 329 that leads to an electric fan assembly 335 (not shown) mounted within the housing 323. The electric fan assembly 335 is preferably realized by a centrifugal design as described above with respect to FIGS. 11A-11E, draws in air from the air intake port 329 and blows the incoming towards an exhaust port 337 preferably disposed near the bottom portion of the housing 323 as shown in FIG. 17A. A grille 333 covers the air intake port 329. The grille 333 may be removable by the user such that the user can access the electric fan assembly 335 for cleaning and maintenance as required.

A clip 351 is secured (or possibly integrally formed) to the housing 323 preferably on a face 353 opposite the grille 333 as shown in FIG. 17B. The clip 351 includes a tab 355 that is sized to slide into and engage the accessory slot of the hard hat 112. Accessory slots are common features of many commercially-available hard hats and are typically disposed on opposite sides of the protective shell (above the ears) and adjacent the rim 114. In this manner, the clip 351 and the accessory slot of the hard hat 112 provide a mounting mechanism for mounting the housing 323 to the hard hat 112 as shown in FIG. 17C. It is also contemplated that other suitable mounting means for securing the housing 323 to the accessory slot of the hard hat can be used in lieu of the clip as shown herein.

A hose 347 extends from the exhaust port 337 of the housing 223. Preferably, the hose 347 is adapted to direct air flow from the exhaust port 337 generally rearward along the rim 114 of the hard hat 110 and then under and around the rim 114 of the protective shell 112 and then generally upwards into the air gap between the user's head and the protective shell 112 for cooling purposes as best shown in FIG. 17C. Note that in view of FIG. 17C, the rear-facing portion 117 of the protective shell 112 is shown, and the front-facing portion of the protective shell 112 is hidden. In the preferred embodiment as best shown in FIGS. 17A-17C, the hose 347 includes a portion 347A that extends from the exhaust port 337 generally rearward in a curved manner along the rim 114 of the hard hat, a second portion 347B that transitions from the first portion 347A generally downward in a curved manner to a 180 degree elbow portion 347C that extends generally below and around the rim 114 of the protective shell 112. An end portion 347D extends from the elbow portion 347C in a generally upward direction. In the preferred embodiment, the hose 347 is constructed of high density polyethylene and is stiff such that the position and orientation of the hose is fixed. Alternatively, the hose 347 can be flexible to allow for desired forgiveness and bendability. The hose 347 can also be pliable and/or extendable to allow for user adjustability of the hose orientation and/or length.

The accessory device 321 includes a battery compartment 361, which is preferably curved to generally conform to the outer surface of the protective shell 112 of the hard hat 110. A clip 361 is secured (or possibly integrally formed) to the battery compartment 361. The clip 361 includes a tab 365 that is sized to slide into and engage the accessory slot of the hard hat 112 similar to the clip 351 for the housing 323. In this manner, the clip 361 and the accessory slot of the hard hat 112 provide a mounting mechanism for mounting the battery compartment 361 to the hard hat 112 as shown in FIG. 17C. It is also contemplated that other suitable mounting means for securing the battery compartment 361 to the accessory slot of the hard hat can be used in lieu of the clip as shown herein.

The accessory device 321 also includes electrical conductors 371 that supply electrical energy from batteries housed in the battery compartment 361 to the electric motor of the electric fan assembly 335 in housing 323. Preferably, the length of the electrical conductors 371 are sized to extend around the front-facing portion of the protective shell 112 near its rim 114.

During use, the housing 323 and the battery compartment 361 are removably mounted on the opposing accessory slots of the hard hat 110. For example, in the illustrative embodiment shown in FIGS. 17A-17C, the housing 323 is removably mounted on the left-side accessory slot when viewed from the back and the battery compartment 361 is removably mounted on the right-side accessory slot when viewed from the back. Such positioning better balances the weight of the cooling device 321 about the perimeter of the protective shell 112. The hose 347 directs air flow from the exhaust port 337 under and around the rim 114 of the protective shell 112 and then generally upwards into the air gap between the user's head and the protective shell 112 for cooling purposes. In the illustrative embodiment, the hose 347 is configured to inject airflow that passes over the back, top and front of the user's head, which provides a maximal cooling effect. Note that the terminal portion of the hose 347 guides the airflow under the rim 114 of the protective shell 112 and ejects it upward into the air gap between the user's head and the protective shell 112.

The housing 323 also supports a printed circuit board (FIG. 18) mounted therein, which includes a microcontroller and associated circuitry as described above. The microcontroller 181 interfaces to switching circuitry (transistor Q3) that selectively closes and opens a current path that allows electric energy supplied by one or more batteries loaded into the battery compartment(s) of the device to power on and off the electric motor of the electric fan assembly 135. The microcontroller 181 also interfaces to a set of two user-operated switches 375A, 375B (which are substitutes for the switches 175A, 175B as shown) that allow the user to control the operation of the electric motor of the electric fan assembly 335 to thereby activate the cooling fan function provided by the device. The first switch 375A is disposed on the housing 323. The second switch 375B, which is preferably realized as an ergonomically designed larger-size button switch as described above, is disposed within the central region of the grill 333 as best shown in FIG. 17A. The second switch 375B also preferably provides tactile feedback that enables the user to operate the switch 375B with work gloves that are commonly used in such dangerous environments.

In the preferred embodiment, the first switch 375A cooperates with the microcontroller 181 to carry out two different operations modes as follows:

-   -   i) Off Mode: the switching circuitry (transistor Q3) is         controlled so that the electric motor of the electric fan         assembly 335 is powered off; and     -   ii) Intermittent Mode: the switching circuitry (transistor Q3)         is controlled so that the electric motor of the electric fan         assembly 335 is automatically cycled on/off for predetermined         on/off time periods (e.g., on for one minute and then off for         five minutes).         Preferably, the power capacity of the battery(ies) held in the         battery compartment(s) of the device, the power consumption         characteristics of the electric motor and the associated control         circuitry, and the predetermined ON/OFF time periods of the         Intermittent mode are adapted such that the electric motor can         operate in the Intermittent mode for an 8 to 10 hour time         period. In this configuration, the intermittent mode is         advantageous because the cooling device 321 can be used to cool         the user for an entire work day (or a substantial part of a long         work day) on a single battery charge. The Intermittent mode has         other advantages. More particularly, during the OFF time         periods, heat and moisture will typically build up under the         protective shell 112 and cause the user to perspire. During the         ON periods, the air blown over the head will enhance the         evaporative-based cooling provided by such perspiration for an         improved cooling effect.

In the preferred embodiment, the second switch 375B cooperates with the microcontroller 181 to carry out a “Fast-Blast” mode wherein the switching circuitry (transistor Q3) is controlled to power ON the electric motor of the electric fan assembly 335 for a predetermined time period (e.g., one minute). In such operations, the “Fast-Blast” mode overrides the “OFF” and “Intermittent” modes such that the “Fast-Blast” mode takes precedence over the control of the switching circuitry and governs the operation of the electric motor.

Referring back to FIG. 17A, the housing 232 (or other part of the device) preferably includes at least one connector 377 that connects to an external power source. The connector(s) 377 can provide a connection to an external AC/DC power converter (outlet charger), an external DC/DC power converter (automobile cigarette lighter charger), and/or an external solar-cell power converter. The external power source can be used to charge the battery(ies) that are held in the battery compartment(s) of the accessory device, and/or possibly for powering the electric fan assembly 335 of the device.

In alternate embodiments, the two-part housing design of FIGS. 17A-17B where the fan housing and the battery compartments are disposed in separate housings can be modified to employ a single housing part that houses both the fan and a battery compartment. In this embodiment, the single housing can be removably secured to the accessory slot of a hard hat by clips or another suitable fixation mechanism.

In yet other embodiments, the two-part or single housing cooling devices as described herein can be removeably secured to the protective shell of the hard hat adjacent the rim by a slot interface or other mechanical fixation means that are formed in (or affixed to) the protective shell.

Advantageously, the cooling airflow provided by the active cooling devices of the present invention can be directed such that it flows over the user's head, which significantly reduces the heat and humidity experienced by the user and greatly enhances the body's evaporative cooling mechanism (perspiration) and thus results in a significant increase in the comfort of the user. Such cooling also reduces the exposure to work related heat exhaustion, potential serious heatstroke while improving worker concentration and productivity. Moreover, such cooling is consistent with the Occupational Safety & Health Administration's guidelines for methods for controlling and preventing heat related illness. The housing also provides crush absorption to absorb shock. Finally, the device's low cost and durable construction affords exceptional return on investment.

In alternate embodiments, the housing of one or more of the devices described herein may be realized from a lightweight, low-cost foam material (or possibly some other material). Such foam material provides additional crush absorption to absorb shock beyond that provided by a rigid plastic housing.

There have been described and illustrated herein several embodiments of a fan-based cooler accessory for a hard hat and related methods of operation. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while particular configurations and materials have been disclosed, it will be appreciated that other configurations and materials can be used as well. Moreover, while the device described above employs an electric fan assembly to actively generating a supply of airflow, other air moving mechanisms (such as an air blower, centrifuge fan or air pump) can also be used. Also, while particular mechanisms for securing the device to the hard hat have been disclosed, other fixation mechanisms that do not rely on drilling, such as suction cups, permanent adhesives, etc. can be used. In some applications, fixation means (e.g., screws, rivets) that employ holes drilled through the protective shell of the hard hat may be used. In addition, while particular control schemes and electronic control circuitry have been disclosed, it will be understood that other control schemes and other electronic control circuitry can be used. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as claimed. 

1. A device for use with head-protection gear that includes a protective shell with a rim, the device comprising: a housing; securing means for removably securing the housing to the protective shell; airflow supply means, supported by the housing, for supplying a flow of air; and a tubular member that extends from the housing, the tubular member directing the flow of air supplied by the airflow supply means under the rim of the protective shell for injection toward space adjacent the user's body, thereby cooling the user's body.
 2. A device according to claim 1, wherein: the securing means comprises an adhesive pad for adhering the housing to the protective shell.
 3. A device according to claim 1, wherein: the securing means comprises a strap that has an encircling configuration for wrapping around the exterior of the protective shell.
 4. A device according to claim 3, wherein: the circumference of the strap is adjustable.
 5. A device according to claim 3, further comprising: a battery compartment supported by the strap, the battery compartment disposed opposite the housing; and at least one electrical conductor supported by the strap.
 6. A device according to 5, further comprising: at least one support member that attaches the electrical conductor to the strap.
 7. A device according to claim 1, wherein: the securing means comprises a plurality of clips that project from the housing for engaging the rim of the protective shell.
 8. A device according to claim 1, wherein: the housing includes curved portions that generally conform to curved rear-portion of the rim of the protective shell, and the securing means comprises clips that project from the curved portions for engaging the rim of the protective shell.
 9. A device according to claim 1, wherein: the securing means includes one or more members that interface to corresponding one or more slots formed in the protective shell.
 10. A device according to claim 1, wherein: the tubular member is adapted such that flow of air supplied by the airflow supply means is injected into an air gap between the user's head and the protective shell and over the user's head.
 11. A device according to claim 1, wherein: the tubular member is flexible and pliable in a manner that enables a user to adjust position and orientation of the tubular member in order to control the direction of the airflow that exits therefrom.
 12. A device according to claim 1, wherein: the length of the tubular member is extendible.
 13. A device according to claim 1, wherein: the housing defines an interior air duct that extends from an opening to the tubular member, wherein the airflow supply means is mounted axially within the interior air duct.
 14. A device according to claim 1, wherein: the housing has a rear-facing intake port leading to the airflow supply means.
 15. A device according to claim 14, wherein: the housing has an exhaust port leading to the tubular member, the exhaust port disposed in its bottom wall.
 16. A device according to claim 15, wherein: the airflow supply means comprises a centrifugal fan assembly.
 17. A device according to claim 14, wherein: the housing has an exhaust port leading to the tubular member, the exhaust port disposed in its front-facing wall.
 18. A device according to claim 17, wherein: the airflow supply means comprises an axial fan assembly.
 19. A device according to claim 14, wherein: the tubular member is removably attached to the housing such that it covers the exhaust port.
 20. A device according to claim 19, further comprising: a grille that is removably attached to the housing such that it covers the exhaust port.
 21. A device according to claim 1, further comprising: a battery compartment that is supported by the housing and holds at least one battery for powering the airflow supply means; and at least one user-manipulated switch and associated control circuitry that are supported by the housing and operate to selectively couple the at least one battery to the airflow supply means in response to user manipulation of the at least one switch.
 22. A device according to claim 21, further comprising: a first user-manipulated switch cooperates with associated control circuitry to operate in the following modes: i) a first mode wherein airflow supply means is powered off; and ii) a second mode wherein the airflow supply means is automatically cycled on/off for predetermined on/off time periods.
 23. A device according to claim 22, wherein: the first user-manipulated switch cooperates with associated control circuitry to operate in a third mode wherein the airflow supply means is continuously powered on.
 24. A device according to claim 22, further comprising: a second user-manipulated switch cooperates with associated control circuitry to operate in a fourth mode wherein the airflow supply means is automatically powered on for a predetermined time period, said fourth mode overriding the operations of the first and second modes.
 25. A device according to claim 24, wherein: the button switch provides an ergonomic design that facilitates finger manipulation by user's wearing gloves.
 26. A device according to claim 21, wherein: the control circuitry comprises a microcontroller that interfaces to switching circuitry that selectively opens and closes a current path between the at least one battery held in the battery compartment and the airflow supply means, the operation of the microcontroller dictated by user manipulation of the at least one switch.
 27. A device according to claim 21, further comprising: a connector that is supported by the housing and connects to an external power source, the external power source selected from the group including an AC/DC power converter, a DC/DC power converter, and a solar-cell power source.
 28. A device according to claim 1, wherein: said housing is realized from a rigid plastic material.
 29. A device according to claim 1, wherein: the airflow supply means comprises one of an electric fan assembly, an air blower, a centrifuge fan, and an air pump.
 30. A device according to claim 1, wherein: the head-protection gear is a hard hat.
 31. A device according to claim 1, wherein: the head-protection gear is one of a military helmet, motorcycle helmet, a helmet for alpine skiing and/or snowboarding. 